Rotozoom Image Optimizer — User Manual
Faster pages through next-generation image compression. Image Optimizer compresses and converts your store's images to modern AVIF and WebP formats, optimises automatically on upload, processes your entire media library in bulk, and keeps a backup of every original.
- Free version: AVIF/WebP conversion on upload, trim & resize, SEO filename renaming, browser-based AI background removal, up to 30 images per day.
- Pro version: unlimited images per day, and cloud AI bulk background removal.
- Pro price: €49 / year per site.
For newcomers: what this plugin does
Photos are usually the heaviest part of an online shop, and heavy pages load slowly — which frustrates customers and hurts your ranking on Google. Image Optimizer fixes this by shrinking the file size of your images without you noticing a drop in quality, and by saving them in AVIF and WebP, formats that are far smaller than old JPEG/PNG files while looking just as good.
It does this automatically when you upload a new image, and it can process the thousands of images already in your store in one bulk run. Every original is backed up first, so nothing is lost.
Setup
1. Check your server supports modern formats
AVIF and WebP need the right image library on your hosting (Imagick or GD with AVIF/WebP support). Most modern hosts have this; the plugin's status screen tells you what is available. If AVIF is unavailable, the plugin still produces WebP.
2. Choose your optimisation settings
In the plugin settings you control:
- Output formats — AVIF and/or WebP.
- Max image size — a maximum width/height; larger uploads are scaled down.
- Trim, resize and pad-to-square — tidy inconsistent product photos into uniform dimensions.
- Keep originals — recommended; lets you restore at any time.
3. Optimise on upload, then bulk-process the rest
New uploads are optimised automatically. To handle your existing library, run a bulk optimisation from the plugin's tools screen.
Feature reference
AVIF & WebP conversion
Converts JPEG/PNG/WebP source images into AVIF (smallest) and WebP (widely supported). The store then serves the modern format to browsers that support it, falling back gracefully where needed — so pages get lighter with no visual change.
Trim, resize & pad-to-square
Cleans up product photography:
- Trim removes empty borders.
- Resize enforces a maximum dimension.
- Pad to square places images on a square canvas so every product tile is consistent.
SEO filename renaming
Renames image files to clean, descriptive, keyword-friendly names instead of IMG_4821.jpg. Descriptive filenames help images rank in Google Image search and improve overall on-page SEO.
Backup of originals
Before any change, the original file is stored so you can restore it later. This makes optimisation safe to run on a live store.
AI background removal
Remove the background from product photos for a clean, catalogue-style look:
- Free — local (browser) removal: the cut-out runs in your own browser, image by image. Private and free, ideal for occasional use.
- Pro — cloud bulk removal: offload background removal to the cloud and run it across many images at once, far faster for large catalogues.
Daily limits
- Free: up to 30 images per day.
- Pro: unlimited images per day — necessary when bulk-converting a whole store.
Free vs Pro at a glance
| Feature | Free | Pro |
|---|---|---|
| AVIF conversion on upload | ✓ | ✓ |
| Trim, resize & pad-to-square | ✓ | ✓ |
| SEO filename renaming | ✓ | ✓ |
| Local AI background removal (browser) | ✓ | ✓ |
| Images per day | up to 30 | unlimited |
| Cloud AI bulk background removal | — | ✓ |
Advanced notes
- Bulk processing & server limits: on some hosts background ("loopback") requests are blocked, so very large bulk jobs run through the browser tab — keep it open until the run completes.
- Quality vs size: AVIF typically saves more than WebP at the same visual quality; enabling both gives the best coverage across browsers.
- Restoring: because originals are backed up, you can revert an image or re-run optimisation with different settings at any time.
Troubleshooting
- AVIF not generated — your server may lack AVIF support; the plugin status screen shows what is available, and WebP will still be produced.
- A bulk run stops partway — re-open the tools page and resume; keep the browser tab active for large jobs.
- Hit the daily limit — the Free plan allows 30 images/day; upgrade to Pro for unlimited.
To connect a Pro licence, see Installing and updating plugins.